The present invention relates to a method and an indicator light system to provide an enhanced visual indication of an operable high-temperature status in an appliance.
Numerous appliances require a waiting period for heated elements to reach an operable temperature before the appliances can be used for their intended purposes. Examples of such appliances include laminators, binding machines, heat sealing machines, ovens, etc. Laminators are machines that apply a polymer film over a substrate to improve the durability of the substrate. Though laminators are better known for the application of polymeric films to paper documents, they are generally known for applying a protective medium on other substrates, such as for example, sealing food in polymer pouches.
Lamination is generally recognized to be a process requiring a heat source and a machine for applying a pressure to a thin laminate material to seal a substrate. As one example, a document is fed into a laminator where a film is applied to the document, then pressurized and heat treated so that the film forms a transparent overlay that protects the document. Usually, the heat source is a hot roller, hot plate, cavity heat source, or thermal print head/platen assembly which is applied to a thin film mechanically positioned to force the film against the document.
The heat source typically converts electrical energy to thermal energy with a resistive heating element. This heat conversion process is a slow process. Moreover, as the document is fed through the laminator, the heated element cools quickly and may need to be reheated before it is able to laminate the next document. Without properly reheating the element, the next attempt at lamination may provide poor lamination or adhesion of the laminated layer. Furthermore, on occasion, the heating element may become overheated. Any attempt at lamination when the heating element is overheated my result in scorched or melted film and/or damaged substrate. It is therefore not surprising that various methods have been tried to make sure the laminator is used only when the heating element is within the operable temperature range.
For manually operated laminators, it is desirable to provide a means to notify the operator that a heating element has reached the appropriate temperature to laminate a substrate. Means for providing a visual indication that the heating element has reached the desired temperature are well-known. The most common method is a light indicator that illuminates when the desired temperature is reached. However, common light indicators are often too dim, and/or not sufficiently sensitive to provide a reliable indication that the appropriate temperature is reached. It would be desirable to provide an enhanced visual indication that heated elements in an appliance have reached the desired temperature.
In U.S. Pat. No. 5,982,969, Sugiyama et al. discloses an optical transmission tube (herein xe2x80x9clight tubexe2x80x9d) that transmits light at the side surface, is flexible, and does not require inordinate amounts of power. According to Sugiyama et al., such a tube can be made by forming a tubular cladding with a core within the cladding that has a higher index of refraction than the cladding, and includes a strip of reflecting layer extended between the cladding and the core. Such a system may provide a means to amplify the effect of a relatively dim light source, such as, for example, a temperature indicator light.
The present invention provides an indicator system and a method to provide an enhanced visual indication of a operative high-temperature status in an appliance. Further, the present invention is also directed to appliances, in particular laminators, incorporating such indicator systems and using such methods.
In one embodiment, an indicator system comprises a light source that provides light to a linear light enhancer. The linear light enhancer transmits light form the light source (preferably an LED) along the length of the linear light enhancer (preferably a light tube), to increase the ability of an appliance operator to observe the light from the light source. Another embodiment includes incandescent light as a light source. In a further embodiment, the light enhancer is an optical fiber. In another embodiment, the light enhance is a light tube, as defined herein. Further embodiments include the incorporation of such indicator systems in appliances that require a heating period, such as for example, laminators.